Reversed-phase high-performance liquid chromatography–fluorescence detection for the analysis of glutathione and its precursor γ-glutamyl cysteine in wines and model wines supplemented with oenological inactive dry yeast preparations

El pdf del artículo es la versión pre-print.A reversed-phase high-performance liquid chromatography-fluorescence detection methodology involving a pre-column derivatization procedure using 2,3-naphtalenedialdehyde in the presence of 5 and 0. 5 mM of dithiothreitol to determine total and reduced glutathione (GSH) and γ-glutamyl-cysteine (γ-glu-cys) in musts and wines has been set up and validated. The proposed method showed good linearity (R 2 >99% for reduced and total GSH, and R 2 >98% for γ-glu-cys) in synthetic wines, over a wide range of concentration (0-10 mg L -1). The limits of detection for reduced GSH in synthetic and real wines were almost the same (0. 13 and 0. 15 mg L -1, respectively) and slightly higher for γ-glu-cys (0. 24 mg L -1). The application of the method allowed knowing, for the first time, the amount of total and reduced GSH and γ-glu-cys released into synthetic wines by oenological preparations of commercial inactive dry yeast (IDY). In addition, the evolution of these three compounds during the winemaking and shelf life (0-9 months) of an industrially manufactured rosé wine supplemented with a GSH-enriched IDY showed that although GSH is effectively released from IDY, it is rapidly oxidized during alcoholic fermentation, contributing to the higher total GSH content determined in wines supplemented with GSH-enriched IDYs compared to control wines. © 2011 Springer Science+Business Media, LLC.IAO and JJRB acknowledge CAM and CSIC for their respective research grants. This work has been founded by PET2007-0134 project.Peer Reviewe

Analyse de l’identité féminine dans la littérature arabo-américaine

Cette thèse étudie des œuvres littéraires arabo-américaines contemporaines écrites par des femmes, plus spécifiquement les écrits d’Evelyn Shakir tels que Bint Arab, ainsi que plusieurs autres romans dont Arabian Jazz et Crescent de Diana Abu Jaber, The Inheritance of Exile de Susan Muaddi Darraj, The Night Counter d’Alia Yunis, et Once in a Promised Land de Laila Halaby. Elle montre comment ces œuvres construisent des univers où peuvent être interrogées les notions d’identité, de culture, d’ethnicité, et de genre. Les conflits quotidiens autour de l’identité sont traités en se fondant à la fois sur les œuvres critiques des femmes arabo-américaines et sur les études psycho-sociales du biculturalisme. De plus, ce travail met l’accent sur la formation de solidarités entre les femmes de couleur, en élargissant le concept de « conscience des zones frontalières » d’Anzaldua pour inclure les œuvres des écrivaines arabo-américaines. Les théories développées après la colonisation, particulièrement les études sur l’orientalisme à la suite d’Edward Said, sont également invoquées pour remettre en question le modèle oriental de la féminité. Enfin, cette thèse analyse la narration et son rôle dans la création d’un point d’ancrage pour les identités « exilées », insistant plus particulièrement sur la figure de Shéhérazade. Ce travail montre ainsi la façon dont les productions littéraires peuvent créer de nouveaux espaces pour comprendre les problèmes sociaux, politiques, culturels, ou ethniques.This dissertation analyses contemporary Arab-American literary productions by female writers, specifically, Shakir’s collection of memoirs Bint Arab and her two short stories “Oh Lebanon” and “Name Calling,” as well as a selection of novels, Abu Jaber’s Arabian Jazz and Crescent, Darraj’s The Inheritance of Exile, Alia Yunis’s The Night Counter, and Laila Halaby’s Once in a Promised Land. It shows how these works construct a space which enables them to investigate questions of identity, culture, ethnicity and gender. Identity conflicts around everyday matters like physical appearance, color, dress codes, veiling, chastity, and marriage are addressed by drawing upon critical works by Arab-American female writers and psycho-social studies on biculturalism. Moreover, this work emphasizes coalition-building with women of color by extending Anzaldua’s concept of the “consciousness of the borderlands” to encompass works by Arab-American female writers. Theories by post-colonial thinkers, particularly Said’s studies on Orientalism, also contribute to the dissertation’s questioning of the Oriental model of womanhood. Finally, this dissertation envisages critical works that study storytelling and its role in creating a surrogate home for “exilic” identities, with special emphasis on the Scheherazadian narrative. This project views literary productions as an appropriate way to investigate social, political, cultural and ethnic issues. It shows how writings by Arab-American women contribute to exploring inner identity conflicts, how they connect with other minority groups, and how they create a new sense of home

Comparison of molecularly imprinted polymers (MIP) and sol–gel molecularly imprinted silica (MIS) for fungicide in a hydro alcoholic solution

International audienceThe aim of this work was (i) to design the best molecularly imprinted silica (MIS) specific for iprodione, a fungicide polluting water, fruits, wine and (ii) to compare the performance of the optimal MIS with its analogue molecularly imprinted polymer (MIP), with the objective to obtained the highest imprinting factor possible. Iprodione was widely used in viticulture. It was recently banned by the European community because of its carcinogenic potential and its presence in or on foods.The binding capacity performance of these polymers was investigated using batch binding studies in hydro alcoholic solutions (10 and 50 %). Langmuir, Freundlich and Temkin models have been used to fit adsorption isotherms. The optimal MIS was obtained using APTMS as functional monomer, low solvent solventvolume and high cross linker quantity during its synthesis. Increasing the quantity of crosslinker and decreasing the solvent volume during the MIS synthesis enhanced the imprinting factor and the binding capacity.The optimal MIS had a higher imprinting factor but a lower binding capacity than the optimal MIP specific to iprodione. The imprinting factor of the optimal MIS was 135 times higher than the optimal MIP. Unlike MIP, MIS kept its molecular recognition nature even under extremely polar media such as the aqueous sample

Chemical Composition, Antioxidant, and Anti-Diabetic Activities of Scorzonera phaeopappa Boiss

International audienceWild edible plants have attracted increasing interest from researchers because of their richness in biologically active phytochemicals. These are found to be a potential remedy for oxidative-stress-mediated diseases such as diabetes mellitus. In this study, total phenol, total terpene, and total flavonoid content as well as antioxidant and antidiabetic activities of Scorzonera phaeopappa Boiss from Lebanon were determined. Using dichloromethane, dichloromethane ammonia, methanol, acetone, and ethanol, extracts were prepared from the edible leaves. The antioxidant activity and the antidiabetic activity were determined by 2,2-diphenyl-1-picrylhydrazyl scavenging, Fe2+-chelating and α-amylase/α-glucosidase inhibitory assays, respectively. Dichloromethane ammonia was found to have the highest extraction capacity on phenols (2.73 mg GAE /100 mg extract) and terpenes (232.42 mg LE/100 mg extract). Methanol was found to have the highest extraction capacity on total flavonoids (63.05 mg QE/100 mg extract). The methanol extract exhibited the highest DPPH scavenging activity (IC50 0.07 mg/mL) and the highest chelating activity as compared to other extracts (0.08 mg/mL, chelating activity 50%). The acetone extract was two times more active than acarbose against α-amylase enzyme and was the most active against α-glucosidase (6.3 mg/mL). Significant positive correlations were observed between total phenol content and α-glucosidase inhibitory assay and total terpene content and α-glucosidase inhibitory assay

Sample Preparation and Analytical Techniques in the Determination of Trace Elements in Food: A Review

International audienceEvery human being needs around 20 essential elements to maintain proper physiological processes. However, trace elements are classified as beneficial, essential, or toxic for living organisms. Some trace elements are considered essential elements for the human body in adequate quantities (dietary reference intakes, DRIs), while others have undetermined biological functions and are considered undesirable substances or contaminants. Pollution with trace elements is becoming a great concern since they can affect biological functions or accumulate in organs, causing adverse effects and illnesses such as cancer. These pollutants are being discarded in our soils, waters, and the food supply chain due to several anthropogenic factors. This review mainly aims to provide a clear overview of the commonly used methods and techniques in the trace element analysis of food from sample preparations, namely, ashing techniques, separation/extraction methods, and analytical techniques. Ashing is the first step in trace element analysis. Dry ashing or wet digestion using strong acids at high pressure in closed vessels are used to eliminate the organic matter. Separation and pre-concentration of elements is usually needed before proceeding with the analytical techniques to eliminate the interferences and ameliorate the detection limits

Antioxidant and anti-diabetic activities in commercial and homemade pomegranate molasses in Lebanon

International audiencePomegranate fruit and its derived products are rich sources of bioactive compounds. They have many biological activities. Pomegranate molasses (PM) is a thick, traditional Middle Eastern syrup used in many recipes for Lebanese and international cuisines. It is a highly nutritious product which makes it of great interest. The purpose of this study was to assess the phytochemical composition, antioxidant and anti-diabetic properties of homemade and commercial PM consumed in Lebanon using samples collected from households in rural areas (n = 4) and the market (n = 28). The objectives of this study were to determine their total phenolic content using the Follin-Ciocalteu method, their total flavonoid content using aluminum chloride method, their antioxidant activity using DPPH radical scavenging as well as ferrous ion chelating assays and their anti-diabetic activity using α-amylase and α-glucosidase inhibitory activities with acarbose, a known anti-diabetic drug, used as the standard reference. Homemade PM samples exhibited a higher antioxidant activity than commercial samples, with the most active homemade PM sample having IC50 values of 0.09 mg/mL (DPPH radical scavenging assay) and 46.78% ferrous ion chelating assay). Homemade PM samples also showed higher anti-diabetic activity than commercial samples, with the most active homemade PM sample having an IC50 of 0.63 mg/mL (α-amylase inhibitory activity) and of 0.41 mg/mL (α-glucosidase inhibitory activity) and being almost as active as acarbose with both enzymes (1.5 times).Significant inverse strong/moderate correlations were observed between total phenolic content/total flavonoid content and the IC50 value of DPPH radical scavenging assay, indicating positive associations between total phenolic and flavonoid contents and antioxidant activity. In addition, significant negative moderate correlations were observed between total phenolic/flavonoid contents and α-amylase inhibitory activity, indicating positive associations between total phenolic and flavonoid contents and anti-diabetic activity

Phytochemical composition, biological activities and antioxidant potential of pomegranate fruit, juice and molasses: A review

International audiencePomegranate fruit and its derived products (seeds, juice and mollassess) have been traditionally used in the prevention and treatment of chronic conditions, including cancer, cardiovascular disease, diabetes, Alzheimer's and arthritis. It has also been widely used in folk medicine as a remedy for conditions of the digestive tract, including parasitic worm infections, ulcers, diarrhea and aphthae. The pomegranate health benefits have been attributed to its bioactive compounds such as phenolic acids, flavonoids and tannins. These bioactive compounds were shown to have antioxidant and anti-diabetic activities as well as anti-inflammatory, anti-carcinogenic, anti-microbial, anti-diarrheal and neuro-protective properties. These pomegranate products are nowadays considered superfood and commonly used in many recipes in international cuisines. They are highly nutritious products rich in secondary metabolites with potent biological activities, which makes their study of great interest to researchers. The current review aimed to provide an up-to-date summary of findings of studies done to investigate the phytochemical composition biological activities, particularly antioxidant property of pomegranate and its products most importantly pomegranate molasses. In conclusion, this review shed the light on the rich phytochemical composition and many potent biological activities especially the antioxidant potential of pomegranate and its products

Detection with flash gas chromatography electronic nose of the general influences of glutathione, ascorbic acid, tannin and carbon dioxide treatments on the volatile profiles of white wines of feteasca regala

The present work aimed to determine some of the influences of the treatments with glutathione (GSH), ascorbic acid (AA), catechinic tannin (T) and carbon dioxide (CO2) during winemaking or bottling on the volatile profiles of white wines of Feteasca Regala. The study is based on the use of a flash gas chromatography electronic nose, which is able to discriminate various clusters of wine samples prepared with various combinations of antioxidants. The treatments that induce enough differences in the volatile profiles of the wine that the electronic nose is able to discriminate are likely to be discriminated also by the consumers. When the electronic nose does not discriminate the clusters of samples with certain treatments it is very likely that those treatments are not sufficient to induce a practically important difference in the aromatic profile of wines. The main detectable influences of the antioxidant treatments are presented and discussed. The treatment of musts with AA (50 mg/l) clearly influences the volatile profile of the wines, reducing their aromatic complexity. The treatment during bottling with catechinic tannin (20 mg/l) does not seem to have an important influence of the profile of the wines produced with the addition of AA and or GSH. The addition of carbon dioxide during bottling does not show much influence one year after bottling, but it shows that in the samples most prone to oxidation, a difference is present. The CO2 treated wines belonging to the cluster of wines treated with 40 mg/l GSH and 50 mg/l AA have distinct profiles, different from those not protected and closer to the clusters of the less oxidised wines. The treatment of musts with GSH shows clear influences at the dose of 40 mg/l, but for the lower dose of 20 mg/l GSH in Feteasca regala wines it is difficult to identify differences compared to the wines included in the cluster of samples not treated with GSH. This finding is particularly relevant as the dose of 20 mg/l GSH is the maximum allowed at present to be added in must and wines